DK2959199T5

DK2959199T5 - FLEXIBLE CORD FOR TRANSPORTING CARBON HYDRADES WITH AN EXTERNAL REINFORCED SEALING CAP

Info

Publication number: DK2959199T5
Application number: DK14718633.2T
Authority: DK
Inventors: Véronique Lachat; Anh-Tuan Do
Original assignee: Technip France
Priority date: 2013-02-25
Filing date: 2014-02-24
Publication date: 2019-02-11
Also published as: AU2014220538A1; MY179919A; FR3002611B1; EP2959199A1; AU2014220538B2; BR112015020482A2; FR3002611A1; BR112015020482B1; EP2959199B1; DK2959199T3; WO2014128422A1

Description

The present invention relates to a subsea flexible pipe intended for transporting hydrocarbons.

The flexible pipe to which the present invention relates is in particular of unbonded type and is used in offshore production. This pipe type is known from US 2007/0119512A1. The flexible pipes used offshore must be able to withstand high internal pressures and/or external pressures and also tolerate twisting or longitudinal bending without risk of rupture. They have various configurations depending on their precise use but in general they satisfy the constructional criteria defined in particular in the API 17 B and API 17 J standards, drawn up by the American Petroleum Institute under the headings "Recommended Practice for Flexible Pipe" and "Specification for Unbonded Flexible Pipe".

Thus, a flexible pipe generally comprises, from the inside to the outside of the pipe: - a structural assembly that is able to withstand radial forces composed of an internal sealing sheath made of plastic, generally a polymer, able to resist to a greater or lesser extent the chemical action of the fluid to be transported, and of a short-pitch helical winding of a metallic element; - at least one ply (and generally at least two crossed plies) of tensile armor wound with a long pitch; and - a protective external sealing sheath made of polymer material, in order to protect the assembly of the pipe and in particular in order to prevent seawater from penetrating into the thickness thereof.

In smooth bore pipes, said structural assembly is formed by said internal sealing sheath and a pressure vault that mainly withstands the internal pressure imposed by the fluid at the wall of the internal sealing sheath over its circumference (circumferential stress or hoop stress) and formed by the short-pitch helical winding around the internal sealing sheath, of one or more metal wires of interlocked shape. In a rough bore pipe, there is also, inside the internal sealing sheath, a metal carcass consisting of an interlocked metal strip, which serves to prevent the collapse of the pipe under the effect of the external pressure. However, the pressure vault also participates in the collapse resistance. The metal carcass and the pressure vault therefore consist of short-pitch wound elements, and they give the pipe its resistance to radial forces, whereas the tensile armor plies consist of metal wires wound with long pitches in order to take up the axial forces. The nature, the number, the sizing and the organization of these layers are essentially linked to the usage conditions of the flexible pipes in question and also to the installation thereof. It should be noted that the various successive layers have a certain freedom to move with respect to one another, which ensures good flexibility of the pipe.

In the present application, the concept of short-pitch winding denotes any helical winding at a helix angle close to 90° and typically between 75° and 90° relative to the longitudinal axis of the pipe. As regards the concept of long-pitch winding, it covers helix angles of less than 55°, typically between 25° and 55°, relative to the longitudinal axis of the pipe.

Whether the pipe is of smooth bore or rough bore type, a protective external sealing sheath is generally extruded around said at least one tensile armor ply having resistance to tensile forces, in order to act as protective sheath of the pipe, in return for which it is subjected to a series of degradations.

In particular, during the installation of flexible pipes on the seabed, the flexible pipe laying systems generally comprise a system for taking up the tension, or tensioner, in order to counter the tensile forces generated by the weight of the suspended pipe and also the movements of the surrounding marine environment. These tensioners are of the linear contact (caterpillar track) type and grip a section of flexible pipe over a certain length of the pipe with at least one pair of opposed endless shoes, the objective being to transfer the gripping force thus exerted on the protective external sealing sheath to the outer armor plies having resistance to tensile forces. The forces exerted are calculated in order to take into account the minimal friction coefficient that exists between the various layers of the pipe located between the caterpillar track shoe and the armor layers of the flexible pipe. The somewhat low value of this friction coefficient makes it necessary to greatly compress the flexible pipe so as to be able to transfer sufficiently large tangential retaining forces. However, the fact of thus increasing the gripping force on the flexible pipe risks degrading the protective external sealing sheath at the area of contact with the shoe.

Another potential source of damaging the outer face of the protective external sealing sheath of the pipe is linked to the provision of an l-tube or J-tube, serving as a guide tube for a flexible pipe, firmly attached to the surface structure (platform), so as to prevent the flexible pipe from undergoing excessively large twisting or bending stresses during its installation or when it is in service. It may be that, when the pipe is subjected to sea movements, or else when the pipe is being brought up through the guide tube, the protective external sealing sheath suffers external abrasion capable of generating microcracks. The use of buoys during the installation may also generate abrasion on the outer face of the protective external sealing sheath of the pipe.

Furthermore, the combined forces on the one hand of the hoop stress that is applied to the walls of the carcass or of the internal sealing sheath and, on the other hand, of the external pressure (or hydrostatic pressure) exerted on the pipe by the surrounding medium, mean that all of the layers of the pipe are greatly compressed with respect to one another, which may also lead to some of them being damaged, in particular the protective external sealing sheath, by abrasion or wear or else by crack initiation and propagation.

In addition, the short-pitch winding, around the tensile armor plies, of tapes that are adhesive and/or reinforced with aramid fibers (for example sold under the brand Kevlar®, Twaron® or Technora®) is known, in particular in order to keep the armor wires in place after the laying thereof, but also in order to limit the “birdcage” swelling of the tensile armor plies, owing to their high tensile mechanical strength along their longitudinal axis. These retaining tapes are typically in the form of relatively flat bundles of rovings of fibers oriented parallel to the longitudinal axis of the tape and assembled together by transverse assembly elements that can be likened to weft yarns, the fiber rovings forming the warp, and it being possible for the retaining tape to be considered to be a woven material. The protective external sealing sheath is then extruded around this tape. However, it happens that the retaining tape thus inserted between the armor layers having resistance to tensile forces and the inner face of the protective external sealing sheath does not remain in position for the entire operating time of the pipe, then revealing the interstices or gaps between the wires of the underlying armor ply, and/or that it deteriorates. Also, in addition to the abrasion generated on the inner face of the protective external sealing sheath by rubbing between said inner face and the underlying tape and/or the armor layer wires, damaging of the protective external sealing sheath by microcrack initiation and propagation is capable of occurring, if the inner face of said sheath were to creep into the interstices between the armor layer wires.

Lastly, damaging of the protective external sealing sheath is capable of weakening the resistance of the pipe with respect to the hoop stresses that it is subjected to, which are linked to the radial force that the hydrocarbon fluid applies to the walls of the carcass or of the inner sealing sheath when this fluid circulates inside the pipe. Short-pitch spiral winding of a pressure vault on top of the internal sealing sheath makes it possible to limit the aforementioned hoop stress phenomenon and therefore makes it possible to prevent the pipe from bursting. However, if there is diffusion of gas into the annular space between the pressure sheath and the protective external sealing sheath and when the pipe is subjected to a high internal pressure, the latter risks being damaged by a blistering phenomenon during a sudden depressurization of the flexible pipe and therefore the resistance of the pipe to the hoop stress is reduced thereby.

Therefore, one problem that is faced and that the present invention aims to solve is to provide a subsea flexible pipe free of the aforementioned limitations. In particular, one objective of the invention is to provide a subsea flexible pipe that makes it possible to improve the abrasion resistance of the protective external sealing sheath.

Another objective of the invention is to provide a subsea flexible pipe which makes it possible to improve the resistance of the protective external sealing sheath to tearing and to the propagation of cracks within it.

Another objective of the invention is to provide a subsea flexible pipe which makes it possible to improve the resistance of the pipe to the hoop stress phenomenon.

For these purposes, the present invention proposes a flexible tubular pipe intended for transporting hydrocarbons produced by a superposition of successive independent layers comprising at least, from the inside outward, an internal sealing sheath, a short-pitch helical winding of a metallic element, at least one tensile armor ply wound with a long pitch and a protective external sealing sheath consisting of an extruded layer made of a polymer comprising two, respectively inner and outer, faces opposite one another, and, according to the invention, said pipe also comprises at least one reinforcing band consisting of a nonwoven material based on fibers that are at least partially embedded inside said polymer of said protective external sealing sheath, in order to mechanically bond together said reinforcing band and said protective external sealing sheath.

Thus, one feature of the invention lies in the use of the reinforcing band made of nonwoven material, that is bonded to the polymer of the protective external sealing sheath, so that the reinforcing band adheres strongly to said sheath, and thus constitutes a reinforcing element thereof, by which the mechanical properties of the protective external sealing sheath, in terms of resistance to the stresses that are exerted on it as recalled above (friction, abrasion, tearing, hoop stress), are greatly reinforced and the protective external sealing sheath may then act as protective sheath of the pipe by being protected from degradations. This feature therefore makes it possible to significantly increase the effectiveness and the service life of the protective external sealing sheath of the pipe.

Thus, according to the invention, the protective external sealing sheath and the reinforcing band are two layers of different natures, distinct from one another, respectively consisting of an extruded layer of a polymer and of a nonwoven material based on fibers at least partially embedded inside said polymer of the sheath. Owing to this particular arrangement, the respective surfaces of the protective external sealing sheath and of the reinforcing band are completely bonded to one another by interpenetration of the fibers of the nonwoven material of the reinforcing band and of the polymer of the extruded layer forming the sheath, by which a strong mechanical bond is created between these layers. The reinforcing band is therefore bonded, via interpenetration, to the polymer of said protective external sealing sheath over the whole of the respective surfaces thereof. Therefore, the reinforcing band adheres strongly to the protective external sheath, thus creating a strong mechanical bond, and this being without adding any additional bonding means, enabling the reinforcement of the protective external sealing sheath.

According to one particular embodiment, said reinforcing band is bonded to said inner face of said protective external sealing sheath, so that said inner face is covered with said reinforcing band, which adheres strongly thereto. Thus, the protective external sealing sheath is protected from wear by internal abrasion against the tensile armor layers and/or against the underlying retaining tape optionally wound with a short pitch around the armor layers. Moreover, such an arrangement improves the resistance of the sheath to tearing and to crack propagation, especially by protecting the sheath from any risk of creep into the gaps between the armor layer wires due to the presence of the reinforcing band based on nonwoven fibers, bonded to the inner face of the sheath and thus forming a protective barrier for the polymer sheath with respect to the armor layer wires.

According to another embodiment, said reinforcing band is bonded to said outer face of said protective external sealing sheath, so that said outer face is covered with said reinforcing band, which adheres strongly thereto. Thus, the protective external sealing sheath is protected from wear by external abrasion and therefore from the risk of the appearance of microcracks that are damaging for its integrity.

According to another embodiment, said reinforcing band is bonded in the middle of said protective external sealing sheath. It other words, said reinforcing band is positioned completely within the thickness of said protective external sealing sheath. In this way, owing to the good mechanical properties of the nonwoven fibers constituting the reinforcing band thus inserted in the middle of the protective external sealing sheath, the mechanical strength of the latter is reinforced in particular with respect to radial forces and therefore the performance of the pipe with respect to the hoop stress phenomenon is notably improved thereby.

The various embodiments set out above may be implemented alone or in combination with one another. Thus, for example, said reinforcing band made of nonwoven material may be positioned on each of the two, respectively inner and outer, opposite faces of said protective external sealing sheath, so as to protect said sheath from abrasion on both its faces. According to this arrangement, said protective external sealing sheath is sandwiched between two reinforcing bands made of nonwoven material, which are mechanically bonded to the polymer material of the protective external sealing sheath, both on the inner face and on the outer face of the latter.

Said reinforcing band preferably consists of a textile layer based on nonwoven short fibers assembled by mechanical compacting and/or adhesive bonding.

Said reinforcing band is positioned with a short-pitch winding at an angle preferably of between 75° and 90°, and advantageously substantially close to 90°, with respect to the longitudinal axis of the pipe. In this way, the reinforcing band is particularly suitable for improving the resistance of the pipe to the hoop stress phenomenon.

As a variant, said reinforcing band may be positioned with a long-pitch winding at an angle of less than 55°, and preferably at an angle of between 25° and 55°, with respect to the longitudinal axis of the pipe.

Advantageously, said nonwoven fibers constituting said reinforcing band are at least partially impregnated, and preferably completely impregnated, with a thermoplastic polymer. The impregnation, even partial, of the nonwoven fibers constituting the reinforcing band makes it possible to improve the adhesion of the fibers with the adjacent polymer layer of the protective external sealing sheath.

Preferably, said fibers are made from a material selected from polyolefins, fluoropolymers, polyesters, acrylics, polyetherimides, polysulfides, polyaryletherketones, aramids, glass and basalt.

Other distinctive features and advantages of the invention will appear on reading the description given below of one particular embodiment of the invention, given by way of indication but nonlimitingly, with reference to the appended drawings, in which: - figure 1 is a longitudinal cross-sectional view of a flexible tubular pipe to which the invention is applied; - figure 2 is a schematic longitudinal cross-sectional view of the protective external sealing sheath of the same pipe modified in accordance with one particular embodiment of the invention; - figure 3 is a schematic longitudinal cross-sectional view of the protective external sealing sheath of the same pipe modified in accordance with another particular embodiment of the invention; - figure 4 is a schematic longitudinal cross-sectional view of the protective external sealing sheath of the same pipe modified in accordance with yet another particular embodiment of the invention.

The pipe 1 having a longitudinal axis 2 comprises from the inside outward a carcass 3 made of an interlocked metal strip, a polymeric internal sealing sheath 4, a metal vault 5 consisting of a short-pitch helical winding of at least one shaped metal wire, an armor layer resistant to axial tension in the longitudinal direction of the pipe and formed from a pair of crossed armor plies 6, 7 with long-pitch winding of metal or composite wires in the opposite direction, and a protective external sealing sheath made of polymer material 8. Owing to the presence of the internal carcass 3, this pipe is referred to as a rough bore pipe, but the invention could just as well be applied to a smooth bore pipe, not comprising an internal carcass. Simply, it would not be outside the field of the invention if other layers, not represented, were provided, according to the type and purpose of the pipe, such as for example a retaining strip consisting of a short-pitch winding of a strip of composite material around the outermost tensile armor ply 7 or an anti-wear strip consisting of a short-pitch winding of a strip of polymer material inserted between the two armor plies 6,7.

The protective sealing sheath 8 is referred to as an external sheath since it is the last constituent layer of the pipe starting from the inside thereof. The protective external sealing sheath has two opposite faces, respectively an inner face 81 and an outer face 82, oriented so that the inner face 81 is directly in contact with the underlying layers of the pipe, whereas the outer face 82 is directly in contact with the medium surrounding the pipe, typically seawater.

The invention allows for the provision of a reinforcing band of the protective external sealing sheath 8, made of nonwoven material in order to specifically reinforce the protective external sealing sheath 8. In accordance with various embodiments of the invention that will be described in detail below, such a band is used by being at least partially embedded inside the polymer material of the protective external sealing sheath 8, so that the reinforcing band is mechanically bonded with the protective external sealing sheath 8 and thus constitutes the reinforcing element thereof.

In accordance with the invention, the reinforcing band of the protective external sealing sheath comprises a fiber-based nonwoven material, or mat, preferably consisting of nonwoven short fibers of a few millimeters, for example having a length of between 1 mm and 50 mm, made from an aramid-type material, known for example under the trade names Twaron® or Technora®; glass; basalt; a polyolefin such as high-modulus polyethylene (UHWMPE) or polypropylene (PP); a fluoropolymer such as polyvinylidene fluoride (PVDF); a polyester such as polyethylene terephthalate (PET); an acrylic such as polyacrylonitrile (PAN); a polyetherimide (PEI); a polysulfide such as polyphenylene sulfide (PPS); a polyaryletherketone such as polyether-etherketone (PEEK) or polyetherketoneketone (PEKK), etc. The fibers are assembled together into one or more layers by mechanical compacting and/or adhesive bonding in order to form a nonwoven, having a thickness preferably of between 0.3 and 5 mm.

The reinforcing band is intended to be wound with a short pitch or else with a long pitch and this winding may be abutting or overlapping between the turns. The reinforcing band moreover forms a layer intended to be wound by being bonded to the polymer layer constituting the protective external sealing sheath with adhesion between them, so as to increase the resistance of the sheath, in particular with respect to tearing and crack propagation. The positioning of the winding of the reinforcing band relative to the protective external sealing sheath is carried out according to various embodiments below.

In accordance with the embodiment from figure 2, the reinforcing band 9 consisting of fibers 10 assembled in order to form a nonwoven or mat is positioned on the outer face 82 of the protective external sealing sheath, so as to form a coating on the outer face 82 of the protective external sealing sheath 8, thus making it possible to avoid external abrasion of the sheath in particular. One method of using the reinforcing band 9 according to this first embodiment during the manufacture of the flexible tubular pipe is the following. A polymer layer intended to form the protective external sealing sheath 8 of the pipe is extruded at a melting temperature around armor layers having resistance to tensile forces and, simultaneously, the reinforcing band 9 made of nonwoven fibers 10 is delivered directly to the outlet of the extrusion head in order to be wound around the outer face 82 of the polymer layer constituting the protective external sealing sheath 8 extruded around the armor layers. The reinforcing band 9 made of nonwoven fibers is applied with a certain pressure suitable for enabling the penetration thereof into the still viscous polymer layer that is in a cooling phase, so that the reinforcing band 9 made of nonwoven fibers and the protective external sealing sheath 8 thus interpenetrate one another at the outer face 82 of the protective external sealing sheath 8, in order to be able to trap the fibers after cooling, thus creating the mechanical bond between the nonwoven reinforcing band 9 and the polymer layer of the protective external sealing sheath 8, at the outer face 82 thereof.

According to one preferred embodiment, the nonwoven fibers 10 constituting the reinforcing band 9 are at least partially impregnated, and preferably completely impregnated, with a binding material, for example of thermoplastic type. Any extruded thermoplastic material is suitable for carrying out the impregnation of the nonwoven fibers 10 of the reinforcing band 9 and the binding material could for example be selected from thermoplastic materials of polyolefin, polyvinylidene, polyamide, polyester, polyaryletherketone, polyarylene sulfone, fluoropolymer, etc. type. In this way, during the winding of the reinforcing band 9 based on nonwoven fibers, the binding material gives the fibers 10 of the reinforcing band 9 good adhesion with the adjacent polymer layer, by impregnation of the respective surfaces thereof.

In order to produce the reinforcing band 9 intended to be bonded to the protective external sealing sheath 8, it is also possible to use an assembly of nonwoven fibers 10 comprising two distinct types of polymer fibers, respectively fibers referred to as “low temperature” fibers (for example of polypropylene type) and fibers referred to as “high temperature” fibers (for example of aramid or polyetheretherketone (PEEK) type). According to this variant, after having wound the reinforcing band 9 around the protective external sealing sheath 8, a polymer layer of the same nature as the “low-temperature” fibers of the assembly of nonwoven fibers 10 is extruded around the reinforcing band 9, i.e. the extrusion temperature of the polymer layer is at least equal to the melting temperature of the “low-temperature” fibers, so as to make these “low-temperature” fibers melt (partial melting). This melting of the “low-temperature” fibers of the assembly of nonwoven fibers constituting the reinforcing band 9 makes it possible to reinforce the mechanical bonds between the polymer layer of the protective external sealing sheath 8 and the reinforcing band 9 wound around. Alternatively, after having wound the reinforcing band 9 around the protective external sealing sheath 8, provision may be made to transport the pipe through an oven that makes it possible to melt the “low-temperature” fibers of the assembly of nonwoven fibers, for the same purpose of reinforcing the mechanical bonds between the polymer layer of the protective external sealing sheath and the reinforcing band.

According to a further variant, in order to produce the reinforcing band 9 intended to be bonded to the protective external sealing sheath 8, it is also possible to use an assembly of nonwoven fibers pre-impregnated with a resin comprising a crosslinking agent. Thus, after winding the reinforcing band 9 around the protective external sealing sheath 8, the resin containing the fibers is crosslinked, thus making it possible to increase the mechanical properties of the coating formed by the reinforcing band 9 bonded to the outer face 82 of the protective external sealing sheath 8 and therefore the resistance of the latter.

In accordance with the embodiment from figure 3, the reinforcing band 9 consisting of fibers 10 assembled to form a nonwoven or mat is positioned on the inner face 81 of the protective external sealing sheath 8, so as to form, this time, a coating on the inner face 81 of the protective external sealing sheath 8, making it possible in particular to avoid internal abrasion of the sheath by the rubbing thereof against the underlying layers. One method of using the reinforcing band 9 according to this embodiment during the manufacture of the flexible tubular pipe is the following.

The reinforcing band 9 made of nonwoven fibers 10 is firstly wound around armor plies having tensile resistance (or around a retaining band previously wound with a short pitch around armor plies intended to reduce the risk of “birdcage” radial buckling). Next, the reinforcing band 9 is coated with a polymer layer extruded around the reinforcing band 9, so as to form the protective external sealing sheath 8 of the pipe. The nonwoven fibers 10 of the reinforcing band 9 wound around the armor plies then absorb the molten polymer material extruded around, which tends to make the viscous polymer material penetrate at least partially into the reinforcing band 9, in order to be able, after cooling, to trap the fibers and thus ensure a good cohesion of the reinforcing band 9 with the protective external sealing sheath 8, on the inner face 81 thereof. This usage method thus makes it possible to have the reinforcing band 9 made of nonwoven fibers 10 bonded to the inner face 81 of the protective external sealing sheath 8.

This usage method may also be combined with the variant described above with reference to the embodiment from figure 2, consisting in using an assembly of nonwoven fibers impregnated with a binding material, making it possible to increase the impregnation of the molten polymer and also the adhesion thereof, or with the variant that consists in using an assembly of nonwoven fibers preimpregnated with a crosslinkable (or thermosetting) resin, or else with the variant that consists in using an assembly of nonwoven fibers comprising both “low-temperature” fibers and “high-temperature” fibers.

In accordance with the embodiment from figure 4, the reinforcing band 9 consisting of fibers 10 assembled in order to form a nonwoven or mat is positioned in the middle of the protective external sealing sheath 8. One method of using the reinforcing band 9 according to this embodiment during the manufacture of the flexible tubular pipe is the following. A first polymer layer is extruded around armor layers having resistance to tensile forces, then the reinforcing band 9 made of nonwoven fibers 10 is wound around this first polymer layer, so that the reinforcing band 9 and the first polymer layer at least partially interpenetrate one another, and the reinforcing band 9 is then coated with a second polymer layer extruded on top of the reinforcing band 9, with an impregnation of the nonwoven fibers 10 of the reinforcing band 9 by the polymer material of this second polymer layer, in order to obtain firm attachment of this second polymer layer and of the reinforcing band 9. This usage method thus makes it possible to have the reinforcing band 9 made of nonwoven fibers 10 bonded in the middle of the protective external sealing sheath 8, consisting of the first and second extruded polymer layers.

As for the preceding embodiments that describe the reinforcing band bonded to the inner face or the outer face of the protective external sealing sheath 8, this embodiment, that describes the reinforcing band bonded in the middle of said sheath, may also be combined with the variants recalled above.

The presence of the reinforcing band made of nonwoven fibers bonded, in accordance with the present invention, to the outer face of the protective external sealing sheath and/or to the inner face of the protective external sealing sheath and/or in the middle of the protective external sealing sheath, according to the various combinations possible between the various embodiments described above with reference to figures 2, 3 and 4, makes it possible: - to improve the resistance to tearing and to crack propagation of the protective external sealing polymer layer; - to improve the internal and/or external abrasion resistance of said polymer layer; - to improve the performance of the pipe with respect to the hoop stress phenomenon; - to improve the thermal insulation performance of the pipe, especially if the fibers of the nonwoven material constituting the reinforcing band are completely impregnated.

Moreover, since the hoop stress performance of the pipe is significantly improved owing to the insertion of the reinforcing band made of nonwoven material in the protective external sealing sheath, it can then be envisaged to reduce the thickness of the protective external sealing sheath, without however sacrificing the resistance of the pipe to hoop stress. This reduction in the thickness of the protective external sealing sheath permitted by the invention is particularly advantageous in that it gives a reduction in the pipe manufacturing costs (reduction in material costs), and also a time-saving in terms of the manufacturing process.

Claims

A flexible tubular conduit (1) for transporting hydrocarbons provided by a superimposed successive independent layer comprising, from the inside to the outside, at least one inner sealing cap (4), a helical coil (5) with a short rise of one metallic element, at least one longitudinally reinforced wood reinforcement layer (6, 7), characterized in that the flexible tubular conduit comprises a protective outer sealing sheath (8) consisting of an extruded layer made of polymeric material comprising two inner and outer opposed surfaces (8, 82, respectively), said sheath comprising at least one reinforcing band (9) consisting of a nonwoven material based on fibers (10) at least partially embedded in the polymer of the protective outer sealing sheath (8) to mechanically bond the reinforcing band (9) and the protective outer sealing sheath (8) together.

The cord according to claim 1, characterized in that the reinforcing band (9) is bonded to the inner surface (81) of the protective outer sealing sheath (8).

Conduit according to any one of claims 1 and 2, characterized in that the reinforcing band (9) is bonded to the outer surface (82) of the protective outer sealing sheath (8).

Conduit according to any one of the preceding claims, characterized in that the reinforcing band (9) is bonded to each of the two respective inner and outer facing surfaces (81.82) of the protective outer sealing sheath (8).

Conduit according to any one of the preceding claims, characterized in that the reinforcing band (9) is bonded in the middle of the protective outer sealing sheath (8).

Conduit according to any one of the preceding claims, characterized in that the reinforcing band (9) consists of a textile layer based on nonwoven short fibers (10) which is assembled by mechanical compression and / or adhesive bonding. .

Conduit according to any one of the preceding claims, characterized in that the reinforcing band (9) is arranged with a short incline at an angle of between 75 ° and 90 ° with respect to the longitudinal axis (2) of the conduit (1). ).

Conduit according to any one of claims 1 to 6, characterized in that the reinforcing band (9) is arranged with a long pitch at an angle of less than 55 ° relative to the longitudinal axis (2) of the conduit (1). .

Conduit according to any one of the preceding claims, characterized in that said nonwoven fibers (10) are at least partially impregnated with a thermoplastic polymer.

Conduit according to any one of the preceding claims, characterized in that the fibers (10) are made of a material selected from polyolefins, fluoropolymers, polyesters, acrylics, polyetherimides, polysulfides, polyaryletherketones, aramides, glass. and basalt.